The remote Oracle Linux 7 / 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2021-9085 advisory.
An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c. (CVE-2021-26932)
In kbd_keycode of keyboard.c, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-144161459 (CVE-2020-0431)
Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (ovl:
stack file ops). This was fixed in kernel version 5.8 by commits 56230d9 (ovl: verify permissions in ovl_path_open()), 48bd024 (ovl: switch to mounter creds in readdir) and 05acefb (ovl: check permission to open real file). Additionally, commits 130fdbc (ovl: pass correct flags for opening real directory) and 292f902 (ovl: call secutiry hook in ovl_real_ioctl()) in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da (ovl: do not fail because of O_NOATIMEi) in kernel 5.11. (CVE-2020-16120)
An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.
(CVE-2021-3347)
nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after- free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup, aka CID-b98e762e3d71. (CVE-2021-3348)
An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to the PV backend, the driver maps grant references provided by the frontend. In this process, errors may be encountered. In one case, an error encountered earlier might be discarded by later processing, resulting in the caller assuming successful mapping, and hence subsequent operations trying to access space that wasn’t mapped. In another case, internal state would be insufficiently updated, preventing safe recovery from the error. This affects drivers/block/xen-blkback/blkback.c. (CVE-2021-26930)
An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions), it isn’t correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.
(CVE-2021-26931)
Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2021-9085.
##
include('deprecated_nasl_level.inc');
include('compat.inc');
if (description)
{
script_id(147204);
script_version("1.5");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/16");
script_cve_id(
"CVE-2020-0431",
"CVE-2020-16120",
"CVE-2021-3347",
"CVE-2021-3348",
"CVE-2021-26930",
"CVE-2021-26931",
"CVE-2021-26932"
);
script_name(english:"Oracle Linux 7 / 8 : Unbreakable Enterprise kernel (ELSA-2021-9085)");
script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 7 / 8 host has packages installed that are affected by multiple vulnerabilities as referenced in
the ELSA-2021-9085 advisory.
- An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations
often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success
or failure of each one is reported to the backend driver, and the backend driver then loops over the
results, performing follow-up actions based on the success or failure of each operation. Unfortunately,
when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively
implying their success from the success of related batch elements. In other cases, errors resulting from
one batch element lead to further batch elements not being inspected, and hence successful ones to not be
possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are
vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and
drivers/xen/gntdev.c. (CVE-2021-26932)
- In kbd_keycode of keyboard.c, there is a possible out of bounds write due to a missing bounds check. This
could lead to local escalation of privilege with no additional execution privileges needed. User
interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-144161459
(CVE-2020-0431)
- Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be
exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was
possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by
the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (ovl:
stack file ops). This was fixed in kernel version 5.8 by commits 56230d9 (ovl: verify permissions in
ovl_path_open()), 48bd024 (ovl: switch to mounter creds in readdir) and 05acefb (ovl: check permission
to open real file). Additionally, commits 130fdbc (ovl: pass correct flags for opening real directory)
and 292f902 (ovl: call secutiry hook in ovl_real_ioctl()) in kernel 5.8 might also be desired or
necessary. These additional commits introduced a regression in overlay mounts within user namespaces which
prevented access to files with ownership outside of the user namespace. This regression was mitigated by
subsequent commit b6650da (ovl: do not fail because of O_NOATIMEi) in kernel 5.11. (CVE-2020-16120)
- An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free
during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.
(CVE-2021-3347)
- nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-
free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a
certain point during device setup, aka CID-b98e762e3d71. (CVE-2021-3348)
- An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to
the PV backend, the driver maps grant references provided by the frontend. In this process, errors may be
encountered. In one case, an error encountered earlier might be discarded by later processing, resulting
in the caller assuming successful mapping, and hence subsequent operations trying to access space that
wasn't mapped. In another case, internal state would be insufficiently updated, preventing safe recovery
from the error. This affects drivers/block/xen-blkback/blkback.c. (CVE-2021-26930)
- An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI
backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially
being at least under the influence of guests (such as out of memory conditions), it isn't correct to
assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running
in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.
(CVE-2021-26931)
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://linux.oracle.com/errata/ELSA-2021-9085.html");
script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3347");
script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
script_set_attribute(attribute:"exploit_available", value:"true");
script_set_attribute(attribute:"vuln_publication_date", value:"2020/09/17");
script_set_attribute(attribute:"patch_publication_date", value:"2021/03/11");
script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/09");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:7");
script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-doc");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-tools");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-tools-libs");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:perf");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:python-perf");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Oracle Linux Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");
exit(0);
}
include('audit.inc');
include('global_settings.inc');
include('ksplice.inc');
include('rpm.inc');
if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
var os_ver = os_ver[1];
if (! preg(pattern:"^(7|8)([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 7 / 8', 'Oracle Linux ' + os_ver);
if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);
var machine_uptrack_level = get_one_kb_item('Host/uptrack-uname-r');
if (machine_uptrack_level)
{
var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
var fixed_uptrack_levels = ['5.4.17-2036.104.4.el7uek', '5.4.17-2036.104.4.el8uek'];
foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
{
audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ELSA-2021-9085');
}
}
__rpm_report = 'Running KSplice level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}
var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '5.4';
if (kernel_major_minor != expected_kernel_major_minor)
audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);
var pkgs = [
{'reference':'kernel-uek-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
{'reference':'kernel-uek-5.4.17-2036.104.4.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
{'reference':'kernel-uek-debug-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
{'reference':'kernel-uek-debug-5.4.17-2036.104.4.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
{'reference':'kernel-uek-debug-devel-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
{'reference':'kernel-uek-debug-devel-5.4.17-2036.104.4.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
{'reference':'kernel-uek-devel-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
{'reference':'kernel-uek-devel-5.4.17-2036.104.4.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
{'reference':'kernel-uek-doc-5.4.17-2036.104.4.el7uek', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-5.4.17'},
{'reference':'kernel-uek-tools-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-5.4.17'},
{'reference':'kernel-uek-tools-5.4.17-2036.104.4.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-5.4.17'},
{'reference':'kernel-uek-tools-libs-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-libs-5.4.17'},
{'reference':'perf-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'python-perf-5.4.17-2036.104.4.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'kernel-uek-5.4.17-2036.104.4.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
{'reference':'kernel-uek-5.4.17-2036.104.4.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
{'reference':'kernel-uek-debug-5.4.17-2036.104.4.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
{'reference':'kernel-uek-debug-5.4.17-2036.104.4.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
{'reference':'kernel-uek-debug-devel-5.4.17-2036.104.4.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
{'reference':'kernel-uek-debug-devel-5.4.17-2036.104.4.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
{'reference':'kernel-uek-devel-5.4.17-2036.104.4.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
{'reference':'kernel-uek-devel-5.4.17-2036.104.4.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
{'reference':'kernel-uek-doc-5.4.17-2036.104.4.el8uek', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-5.4.17'}
];
var flag = 0;
foreach var package_array ( pkgs ) {
var reference = NULL;
var release = NULL;
var sp = NULL;
var cpu = NULL;
var el_string = NULL;
var rpm_spec_vers_cmp = NULL;
var epoch = NULL;
var allowmaj = NULL;
var exists_check = NULL;
if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
if (!empty_or_null(package_array['release'])) release = 'EL' + package_array['release'];
if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
if (reference && release) {
if (exists_check) {
if (rpm_exists(release:release, rpm:exists_check) && rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
} else {
if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
}
}
}
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : rpm_report_get()
);
exit(0);
}
else
{
var tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'kernel-uek / kernel-uek-debug / kernel-uek-debug-devel / etc');
}
Vendor | Product | Version | CPE |
---|---|---|---|
oracle | linux | 7 | cpe:/o:oracle:linux:7 |
oracle | linux | 8 | cpe:/o:oracle:linux:8 |
oracle | linux | kernel-uek | p-cpe:/a:oracle:linux:kernel-uek |
oracle | linux | kernel-uek-debug | p-cpe:/a:oracle:linux:kernel-uek-debug |
oracle | linux | kernel-uek-debug-devel | p-cpe:/a:oracle:linux:kernel-uek-debug-devel |
oracle | linux | kernel-uek-devel | p-cpe:/a:oracle:linux:kernel-uek-devel |
oracle | linux | kernel-uek-doc | p-cpe:/a:oracle:linux:kernel-uek-doc |
oracle | linux | kernel-uek-tools | p-cpe:/a:oracle:linux:kernel-uek-tools |
oracle | linux | kernel-uek-tools-libs | p-cpe:/a:oracle:linux:kernel-uek-tools-libs |
oracle | linux | perf | p-cpe:/a:oracle:linux:perf |
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-0431
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-16120
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26930
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26931
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26932
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3347
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3348
linux.oracle.com/errata/ELSA-2021-9085.html